Genetic Diversity of Featherback Fish in Thailand

Abstract

Four featherback fish of the Family Notopteridae in Thailand, Notopterus notopterus, Chitala ornata, Chitala blanci and Chitala lopis, were studied using allozyme electrophoresis to obtain their genetic diversity informations. With a total of 38 enzyme loci screened, 28 variable loci were found of being allelically different between the four species. Of the 28 variable loci, 11 loci (ADA*, ADH*, FH-2*, G3PDH-1*, G3PDH-2*,IDHP*, IDDH*, LDH-2*, LDH-3*, MPI* and SOD-2*) were found to be polymorphic in N. notopterus, two loci (IDHP* and SOD-2*) in C. ornata and also two loci (IDHP* and MPI*) in C. blanci, while no polymorphic loci were found in C. lopis. The estimated genetic variabilities (P_0.99 , H_e) ranged from P_0.99= 0 and H_e = 0 in C. lopis to P_0.99 = 0.289 and H_e = 0.049±0.017 in N. notopterus. The observed genotypes in any species were not significantly deviated from Hardy-Weinberg equilibrium (χ2_p>0.05), suggesting no significant differences between the samples within a species, while the FST values (above 0.25) and the heterogeneity contingency chi-square analyses (p<0.001) suggested rather large genetic divergence between these species. Genetic structure and relationships of the four species were phylogenetically presented as two separate clades, the N. notopterus clade and the clade of three Chitala species, revealing that the three Chitala species were genetically related more closely to each other than to N. notopterus and consequently supporting the present nomenclature of the fish being used.